All touchpads in this series need a kernel quirk to fix the min/max ranges. It's like a happy meal toy, make sure you collect them all.

A new kernel evdev input prop INPUT_PROP_TOPBUTTONPAD is available in 3.15. It marks the devices that require top software buttons. It will be backported to stable.

A new option was added HasSecondarySoftButtons was added to the synaptics driver. It is automatically set if INPUT_PROP_TOPBUTTONPAD is set and if set, the driver parses the SecondarySoftButtonAreas option and honours the values in it.

If you have the kernel min/max fixes and the new property, don't bother with DMI matching. Provide a xorg.conf.d snippet that unconditionally merges the SecondarySoftButtonAreas and rely on the driver for parsing it when appropriate